Sprint says it will have live LTE sites using former Clearwire spectrum across the U.S. next year and expects all its new mobile devices in 2014 to be equipped for those frequencies -- though not necessarily iPhones.

The company gave an update on progress in its Network Vision upgrade project during a conference call on Tuesday to discuss second-quarter financial results, according to a transcript provided by Seeking Alpha. Earlier this month, the fourth-largest U.S. mobile operator got a shot in the arm with its US$21.6 billion acquisition by SoftBank and also bought out former partner Clearwire.

With the Clearwire acquisition, Sprint got access to an emerging Clearwire LTE network that it plans to use for extra mobile data capacity in densely populated areas. Though it uses a slightly different form of LTE than Sprint's and operates in a relatively short-range spectrum band, around 2.5GHz, the former Clearwire network could give the carrier a large amount of capacity to bolster services in cities.

The network had been intended for Sprint's use through the longstanding partnership between the two companies, but Sprint's takeover of Clearwire gave that plan a more solid foundation.

There were already about 2,000 Clearwire LTE sites completed when the buyout was completed earlier this month, said Steve Elfman, president of network operations and wholesale, on the conference call. He expects several thousand 2.5GHz LTE base stations on the air this year, with sites across the country next year, though not the full deployment of sites that will use the spectrum. The 2.5GHz radios don't have as long a range as Sprint's other gear, so they'll be deployed in a larger number of sites, he said.

Sprint plans eventually to operate LTE in three spectrum bands: Its own 1.9GHz band, the 800MHz frequencies from its defunct Nextel network, and the 2.5GHz spectrum. Earlier this month it introduced the first mobile device that will be able to use all those bands.

The carrier expects to have a few handsets with 2.5GHz capability in the fourth quarter, and starting in 2014, all its new devices will be able to use that spectrum, Elfman said. But asked later on the call whether that would include the Apple iPhone, Elfman clarified that Sprint couldn't say whether Apple would adopt 2.5GHz for that device.

"We can't confirm anything on the iPhone at this time or anytime," Elfman said.